Cowlesite
A zeolite mineral which typically occurs as small white or colourless spheres in basalt.
Often occurs with other zeolite minerals.
Information about Cowlesite
Cowlesite is a rare calcium aluminium silicate zeolite – an unusual member of the zeolite family in that it lacks a confirmed three-dimensional framework structure of the kind that defines most zeolites, and for a long time its structure was incompletely determined.
It forms as delicate, colourless to white orthorhombic platy to acicular crystals, typically very small, in the cavities of basaltic and other mafic volcanic rocks where it grows alongside other zeolites such as phillipsite, chabazite, and thomsonite.
Like all zeolites it is a hydrated aluminosilicate capable of reversible water loss, and its open porous structure can host and exchange cations – the property that makes zeolites industrially important.
Cowlesite is one of the less commonly encountered zeolite species in collections, partly because of its very small crystal size and partly because it lacks the striking habit of some other zeolites. Careful examination of basalt vugs, however, sometimes reveals it as a component of the diverse zeolite assemblages that form by low-temperature hydrothermal alteration of basaltic glass in oceanic island and flood basalt sequences.
Uses and History
Cowlesite was named in honour of John Cowles, an American mineral collector who contributed specimens and enthusiasm to its discovery.
It occurs in the zeolite-bearing basalts of Oregon and Washington, USA; in Iceland, which has exceptionally rich zeolite-bearing volcanic sequences; and in various other basaltic provinces worldwide.
Cowlesite is not a significant British mineral in a collecting context, though zeolite-bearing basalts occur in parts of Scotland and Northern Ireland (particularly the Antrim basalts of the British Tertiary Igneous Province) that have the appropriate lithology and hydrothermal history.
Mineralogy
Hazards and Warnings
No specific hazards are associated with cowlesite under normal handling conditions. Standard precautions apply when cutting.
Almost all rocks, minerals (and, frankly, almost all other substances on earth) can produce toxic dust when cutting, which can cause serious respiratory conditions including silicosis. When cutting or polishing rocks, minerals, shells, etc, all work should be done wet to minimise the dust, and a suitable respirator or extraction system should be used.
Translations
Arabic:
Hindi:
Portuguese:
Bengali:
Indonesian:
Punjabi:
English:
- Cowlesite
Italian:
Russian:
French:
- Cowlésite
Japanese:
Spanish:
- Cowlesita
German:
- Cowlesit
Korean:
Thai:
Gujurati:
Mandarin Chinese:
Urdu: